Field of the Invention
The present invention relates to a wireless communication system, and more particularly, to a method for calculating, by a user equipment (UE), a redistribution range, and a device for supporting the same.
Related Art
3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) that is an advancement of UMTS (Universal Mobile Telecommunication System) is being introduced with 3GPP release 8. In 3GPP LTE, OFDMA (orthogonal frequency division multiple access) is used for downlink, and SC-FDMA (single carrier-frequency division multiple access) is used for uplink. The 3GPP LTE adopts MIMO (multiple input multiple output) having maximum four antennas. Recently, a discussion of 3GPP LTE-A (LTE-Advanced) which is the evolution of the 3GPP LTE is in progress.
Cellular is concept proposed to overcome a restriction of a service region and a limitation of a frequency and subscriber capacity. This is a method of providing communication coverage by changing single high-power base station to a plurality of low-power base stations. That is, a mobile communication service region is divided in unit of several small cells so that different frequencies are assigned to adjacent cells, and two cells which are sufficiently spaced apart from each other and thus have no interference occurrence use the same frequency band to spatially reuse a frequency.
Meanwhile, there may be a particularly high communication demand in a specific region such as a hotspot inside a cell, and reception sensitivity of radio waves may deteriorate in a specific region such as a cell edge or a coverage hole. With the advance of a wireless communication technique, a small cell may be installed inside a macrocell for the purpose of enabling communication in the hotspot, the cell edge, and the coverage hole. A pico cell, a femto cell, a microcell, or the like is a type of the small cell. The small cell may be located inside or outside the macrocell. In this case, the small cell may be located at a position where the macrocell does not reach, or may be located indoors or at the office. Such a network may be called a heterogeneous network (HetNet). In this case, the heterogeneous network does not have to use different radio access mechanisms. In a heterogeneous network environment, the macrocell is a relatively large coverage cell, and the small cell such as the femtocell and the picocell is a small coverage cell. The macrocell and the small cell may serve to distribute the same traffic or transmit traffic of different QoS. In the heterogeneous network environment, coverage overlapping may occur between the plurality of macrocells and small cells.